In the force method of analysis of indeterminate trusses, if the truss is indeterminate to degree one, the change in length of redundant, member due to unit force is found by using the formula where A is cross-sectional area
I – Moment of Inertia
n – force in the member due to unit load application
N – force in the member due to actual load
E – Modulus of Elasticity
1
\(\sum \frac{{nNL}}{{EI}}\)
2
\(n\sum \frac{NL}{AE}\)
3
\(\sum \frac{nNL}{AE}\)
4
\(\sum \frac{NL}{AE}\)